Anker Nano MagSafe Portable Charger, Ultra-Slim 5,000mAh Magnetic Wireless Power Bank, Qi2-Certified 15W Max, Compact for Travel, Ergonomic Design, for iPhone 17/16 Series, and More

There are many ways you can go in terms of shapes/sizes and companies (although Anker is what I would recommend), but time and time again I keep going back to this one: https://www.amazon.com/Anker-Ultra-Slim-Certified-Ultra-Fast-MagSafe-Compatible/dp/B0F8J4WK57 While its MagSafe compatible, I would suggest grabbing this cable too (one of the best Ive come across): https://www.amazon.com/Rixmie-Charging-Thunderbolt-External-Transfer/dp/B0B49WCQX4 The reason for the cable is that with any magnetic type battery you tend to lose some power due to heat transfer inefficiency and that cable is both tiny and really good quality/well built so you can just fold it back between the battery and the phone and when you have the battery snapped on the back of your phone and plug it in it disabled the MagSafe charging and charges it via the USB-C. I've noticed that that battery size and weight is pretty much the perfect one for travel since it's super thin and light and effectively gives you a full second charge. If you need something heavier and larger due to multiple devices or very heavy usage/multiple days, I would recommend this specific model: https://www.amazon.com/dp/B0DMDJBCDP?ref=ppx_pop_mob_ap_share It's both well built and the two built-in cables come in really handy. The downside is that it's heavy but if you're going to carry your backpack with you throughout the day it really becomes the single source of charging. I also bring this one with me whenever I know that I can't get back to a charger by the evening or have train travel/multiple airplanes.